AirHint found the following cheapest return flights from Ontario (ONT) to San Jose (SJO) in January 2026 (see full year).

Return flights

20 Jan - 27 Jan	Avianca
15 Jan - 27 Jan	Frontier Airlines
19 Jan - 29 Jan	Southwest Airlines
28 Jan - 04 Feb	Southwest Airlines
13 Jan - 20 Jan	Avianca
28 Jan - 30 Jan	Southwest Airlines
29 Jan - 02 Feb	Southwest Airlines
29 Jan - 01 Feb	Avianca
29 Jan - 07 Feb	Avianca
31 Jan - 07 Feb	Avianca
20 Jan - 04 Feb	Southwest Airlines
21 Jan - 25 Jan	Southwest Airlines
15 Jan - 18 Jan	Avianca
15 Jan - 20 Jan	Avianca
07 Jan - 12 Jan	GOL Linhas Aéreas
30 Jan - 04 Feb	Southwest Airlines
16 Jan - 19 Jan	Frontier Airlines

Also check the deals for one-way flights from Ontario to San Jose in January.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

Book a cheap hotel in San Jose

Cheap car rent in San Jose

Cheapest return flights from Ontario to San Jose in January from $365

Return flights